Federal prosecutors challenged the "broken marriage" defense Monday in the corruption trial of the former governor and first lady of Virginia.

Defense attorneys have suggested that Bob and Maureen McDonnell could not have conspired to provide special favors to former Star Scientific Inc. CEO Jonnie Williams in exchange for more than $177,000 in gifts and loans while McDonnell was in office, because their marriage was crumbling and they were barely talking.

Prosecutors showed Monday that the couple vacationed together 18 times in 22 months. They also showed pictures of the McDonnells arriving at court holding hands earlier this year.

Prosecutors also tried to show that McDonnell was very involved with his finances and desperately needed money that eventually came from a wealthy businessman, former Star Scientific Inc. CEO Jonnie Williams.

The cross-examination of Bob McDonnell was contentious from the start Monday.

The pointed questions prompted long pauses and lengthy explanations from McDonnell, who was admonished by the judge to just “answer the question” when he tried to offer a detailed response of why he disagreed with a question that implied that a joint real-estate venture he owned with his sister was in financial trouble.

Just 10 min. into cross-exam & judge already jumped in saying "that doesn't answer the question" as #McDonnell tried a long explanation

The money issues are key because prosecutors have said McDonnell's financial desperation is what prompted him to accept cash and gifts from Williams. McDonnell says he considered Williams a friend and that he had been making steady progress in reducing his family's debt even without Williams' help.

Prosecutor Michael Dry asked McDonnell about a series of emails from staffers in which they speculated that Maureen McDonnell was drawn to Williams because “he's loaded.” McDonnell, after initially demurring, said he didn't believe his wife was drawn to Williams for his money.

“Money? That wasn't the reason for friendship, no,” McDonnell said. But asked whether his wife had a long history of making inappropriate financial requests of friends and family, McDonnell agreed.

New revelations even on day 21: Bob #McDonnell knew his wife had a history of making inappropriate requests for money b4 Jonnie Williams

The cross-examination began with McDonnell acknowledging that he knew Williams had loaned him and his wife $120,000 and provided numerous expensive gifts, including $15,000 to pay for catering at the wedding of the McDonnells' daughter, personal vacations in Cape Cod and Smith Mountain Lake, and golf outings.

During three days on the stand in direct examination, McDonnell downplayed his knowledge about some of the gifts, saying he did not learn about them until after the fact or that they had been arranged by his wife.

For example, McDonnell said he did not know at the time that Williams spent $19,000 on designer clothing for Maureen McDonnell on a Manhattan shopping spree. Dry asked McDonnell if he was testifying that, despite his knowledge of his wife's inappropriate financial requests and Williams' lavish spending on other occasions, it never occurred to him that Williams might pick up the tab.

"That's exactly what I'm testifying to," McDonnell said.

"Okay," Dry said, suggesting disbelief.

Dry also questioned McDonnell's truthfulness on other Jonnie Williams gifts, like the $50,000 loan to Maureen McDonnell in 2011. Bob McDonnell had testified that he was very upset when he learned about the loan. But if he was so angry, wondered Dry, why did it take Bob McDonnell 30-45 days to contact Williams about the money.

“You didn't just immediately pick up the phone and say, ‘Hey, Mr. Williams, you just loaned my wife $50,000 and we don't need it,’” Dry asked.

“No,” McDonnell said.

A subdued, soft-spoken McDonnell answered questions from his wife's attorney Monday morning. He was so quiet in some of his responses that the judge asked him to "speak up," adding, "I'm having trouble hearing you today."

Maureen's defense attorney William Burck showed the court several emails and text messages between Jonnie Williams and the former governor. Burck walked the court through several of the gifts and loans that prosecutors allege were given to the McDonnells in exchange for promotion of Star Scientific.

Bob McDonnell's responses to each gift and loan suggested there was little communication between him and his wife, let alone conspiracy.

Before concluding his questioning of the former governor, Maureen's defense attorney asked Bob, "Did [Maureen] ever make any effort to get you to do something, anything, in exchange for gifts and loans from Jonnie Williams?"

"No," McDonnell replied.

McDonnell started the morning testifying that his troubled marriage to Maureen stretched back several years.

In a September 2011 email Maureen's defense attorney entered into evidence, Bob wrote to his wife that her "fiery anger and hate... has become and more frequent." He testified that he "prayed about her anger."

McDonnell said publicly his wife handled her duties well as first lady of Virginia.

"Privately," he continued. "The way she dealt with me and her treatment of the staff was just unacceptable and we need to do better."

McDonnell told the court that in 2012 his wife got mental health treatment and medication.

"Do you think you did enough to help your staff with Maureen McDonnell?" Maureen's defense attorney asked.

"No," McDonnell responded. "I wish I would've done more.... At the time I did a number of things; I did the best I could."

McDonnell took the stand for the first time late last week, testifying about nearly every interaction he had with Williams, saying he didn't find it inappropriate to accept two loans from him totaling $70,000 because Williams didn't ask him for anything significant in return.

"All he'd asked me for was to call his father for his 80th birthday, which I did," McDonnell testified.

The McDonnells are on trial in federal court, accused of accepting more than $177,000 in gifts, loans and trips from Williams, the former CEO of Star Scientific Inc., in exchange for promoting his company's dietary supplements.